During the production of semiconductor devices using x-ray lithography, x-rays must be collected from a source and directed down a beamline. The x-rays travel down the beamline to devices such as steppers that use x-rays for photolithography. A schematic view representative of an x-ray lithography system is shown in FIG. 1. The x-ray lithography system 10 includes an x-ray source 12, beamlines 14 and x-ray lithography devices 16.
An electron travels down a vacuum tube 18. As the electron travels down the vacuum tube 18, a bending magnet (not shown in this figure) bends the path of the electron. When an electron curves, it emits x-rays at a an angle tangent to the electron's path. A stream of bending electrons constitute the x-ray source 12. The apparatus which accelerates the electrons, providing the x-ray source is commonly referred to as a synchrotron. The x-rays produced by x-ray source 12 are collected by the interface 20 and sent down the beamlines 14.
Conventional x-ray interfaces collect only a small portion of the available x-rays. This can be a significant disadvantage because a significant amount of power is wasted and unavailable for use in the x-ray lithography. Turning now to FIG. 2, FIG. 2 is a cross-sectional view illustrating a conventional interface for channeling the x-rays down beamlines 14. An electron travels down the vacuum tube 18. As the electron curves it emits x-rays tangentially to its path. A typical synchrotron curves the electrons such that a 30 degree fan of x-rays are emitted towards the interface. A portion of the x-rays emitted are collected through slots 34. These x-rays then travel down beamlines 14 to an x-ray photolithography device (not shown in this figure).
Because of the size of the slots 34, each beamline is only able to collect approximately two degrees out of the 30 degrees of x-rays that are available. For the three beamlines 14 at the source (curve in electron path) this amounts to only 20 percent of the available x-rays being used. The remaining 80 percent is absorbed by the wall of tube 18, creating heat.
Additionally, the conventional interface also limits the number of beamlines that can be attached to an x-ray source. The beamlines are attached to the vacuum tube 18 with flanges 38. The size of the flanges 38 limits the proximity of the beamlines, thus the beamlines cannot be spaced as close together as would be desired. The more beamlines that could be attached to an x-ray source, the more x-ray lithography devices that can be supplied by a single x-ray source.
Because the beamlines 14 must be spaced far apart, there is a substantial space between the slots 34. These spaces absorb, as heat, the x-rays not collected by the slots. If not controlled this excess heat can cause the electrons to be deflected in their orbital path, resulting in process control difficulties. Therefore expensive and wasteful cooling mechanisms must be used to control interface temperature.
Furthermore, due to space constraints, in the conventional design the first mirrors for collecting and focusing the beamlines are typically located at least 3 meters down the beamlines from the slots 34. This results in collection of an even narrower portion of the horizontal fan of x-rays.
Consequently, it is desirable to have an x-ray interface that is able to collect a greater percentage of the available x-rays. Also, it is desirable to have an interface that is able to supply a greater number of beamlines from a x-ray source.